Laser-mig arc hybrid welding apparatus and hybrid welding method

Abstract

The present application relates to a kind of laser-MIG electric arc composite welding device and composite welding method for curve weld.The composite welding device includes: laser welding processing head and arc welding gun, the laser beam output by the laser welding processing head and the MIG electric arc output by the arc welding gun act on the same molten pool, and the arc welding gun can be rotated around the straight line direction as axis where the laser beam is located.Laser electric arc composite welding method includes the steps of robot demonstration, welding track compensation correction, motion control programming, laser electric arc synchronous motion welding and the like.The embodiment of the present application avoids the problem of producing fusion defect and / or undercut defect, is suitable for in the process of curve weld welding, and is beneficial to improve the welding quality of curve weld.

Description

Technical Field

[0001] This invention relates to the field of material welding technology, and in particular to a laser-MIG arc hybrid welding device and hybrid welding method for curved welds. Background Technology

[0002] Laser-arc hybrid welding combines two heat sources with drastically different physical properties and energy transfer mechanisms, applying them simultaneously to the same processing position. This fully leverages the advantages of each heat source while compensating for their respective shortcomings, resulting in a novel and highly efficient welding method. Among these methods, laser and arc off-axis hybrid welding is the most widely used and mature, with commonly used arcs including MIG and TIG arcs.

[0003] See appendix Figure 1 and attached Figure 2 As shown, in laser-arc hybrid welding, the laser beam 1 and the arc welding torch 2 are often arranged one in front of the other, with the central axis 10 of the laser beam 1 and the arc welding torch 2 being basically tangent to the welding trajectory 3. Due to the additional effect of the arc heat source of the arc welding torch 2, the weld width on the front side of the molten pool 9 is much wider than that in self-fusion laser welding. When achieving deep penetration welding of thin-walled metal materials, the weld width on the front side of the molten pool 9 is much larger than that on the back side, so the cross-section of the hybrid weld often exhibits a shape that is wider at the top and narrower at the bottom. Under the influence of the arc action zone 8 formed by the laser welding aperture 7 and the arc column, the molten pool 9 in the hybrid welding undergoes a violent heat and mass transfer process.

[0004] Please refer to the appendix for further details. Figure 1 and attached Figure 2 As shown, when welding curved welds, in addition to the existing thermal effects within the molten pool 9, the molten pool 9 is also subject to centrifugal force. Since there is relatively more liquid metal at the top of the molten pool 9, the centrifugal force on the liquid metal in this area is relatively large. When the radius of curvature of the curved weld is large, this centrifugal force drives the liquid metal to flow outward. At this time, the surface tension of the liquid metal will counteract the influence of the centrifugal force, thus causing the molten pool 9 to tend to maintain a relatively balanced state with a centrally symmetrical structure. When the radius of curvature of the curved weld is less than a certain threshold, the centrifugal force on the liquid metal at the top of the local molten pool 9 may be greater than the surface tension in that area. The liquid metal in this area will tend to flow towards the solidified metal 4 on the outer side, causing the weld face formed by the solidification of the molten pool 9 to be prone to undercut defects 6 near the weld toe on the inner side of the curve, while the weld face is prone to poor fusion defects 5 at the weld toe on the weld face away from the inner side of the curve.

[0005] Poor fusion defects (5) or undercut defects (6) at the weld toe on the weld face will weaken the mechanical properties of the welded joint, especially its fatigue performance. Therefore, these welding defects should be avoided as much as possible. Currently, although these welding defects can be eliminated through post-weld laser repair welding or other methods, these are remedial measures. They not only affect the normal welding operation progress, leading to low welding production efficiency, but also cause secondary heating to the welded joint, easily resulting in coarsening of the welded joint grains and microstructure, and a reduction in mechanical properties. Summary of the Invention

[0006] (1) Technical problems to be solved

[0007] The first aspect of this invention provides a laser-MIG arc hybrid welding device for curved welds. The hybrid welding device includes a laser welding head and an arc welding torch. The laser beam output from the laser welding head and the MIG arc output from the arc welding torch act on the same molten pool, and the arc welding torch can rotate around the axis of the line containing the laser beam. This invention avoids problems such as poor fusion defects and / or undercut defects, is suitable for curved welds, and helps improve the welding quality of curved welds.

[0008] The second aspect of this invention proposes a laser-MIG arc hybrid welding method for curved welds, including steps such as robot teaching, welding trajectory compensation and correction, motion control programming, and synchronous laser-arc welding. This invention is applicable to the welding process of curved welds and helps improve the welding quality of curved welds.

[0009] (2) Technical solution

[0010] A first aspect of the present invention provides a laser-MIG arc hybrid welding device, mainly used for curved welds, the device comprising:

[0011] A laser welding head, used to output a laser beam for welding;

[0012] An arc welding torch, specifically a MIG welding torch, is used to output a MIG arc for welding.

[0013] The laser beam output from the laser welding head and the MIG arc output from the arc welding gun act on the same molten pool, and the arc welding gun can rotate around the straight line direction of the laser beam as an axis.

[0014] Furthermore, the laser-MIG arc hybrid welding device also includes:

[0015] Connecting seat, the laser welding head is mounted on the connecting seat;

[0016] A clamping assembly is rotatably connected to the connecting seat and is used to clamp the arc welding gun and keep the arc welding gun in a preset tilt state.

[0017] A driving component is used to drive the clamping component and the arc welding gun to rotate or position themselves around the linear direction of the laser beam.

[0018] Furthermore, the connecting seat includes a horizontal plate and a sleeve. The side of the laser welding head that outputs the laser beam is disposed on the horizontal plate. The sleeve has a through hole in the middle for transmitting the laser beam. The central axis of the sleeve coincides with the line where the laser beam is located.

[0019] Furthermore, the clamping assembly includes a rotating sleeve and a clamping arm. The rotating sleeve is sleeved on the outer peripheral wall of the sleeve, and a bearing is provided between the rotating sleeve and the sleeve. One end of the clamping arm is fixed to the outer peripheral wall of the rotating sleeve, and the other end of the clamping arm is connected to the arc welding gun.

[0020] Furthermore, the driving assembly includes a driving device for driving the rotating sleeve to rotate or position itself around the linear direction of the laser beam as a rotation axis.

[0021] Furthermore, one end of the outer peripheral wall of the sleeve is provided with an annular boss, and the other end of the outer peripheral wall of the sleeve is provided with an external thread. The rotating sleeve is sleeved between the annular boss and the external thread, and the external thread is threadedly connected with a threaded retaining ring.

[0022] Furthermore, the drive assembly also includes a first gear, and a second gear is provided on the outer peripheral wall of the rotating sleeve, wherein the first gear and the second gear mesh with each other for transmission.

[0023] Furthermore, the driving device is fixed on the connecting seat, and the driving shaft of the driving device is parallel to the rotation axis of the rotating sleeve.

[0024] A second aspect of this invention provides a laser-MIG arc hybrid welding method for curved welds, applied to the laser-MIG arc hybrid welding apparatus for curved welds described in any of the first aspects of this invention. The laser-MIG arc hybrid welding method includes the following steps:

[0025] Robotic arm teaching: The laser-MIG arc hybrid welding device is driven by a robotic arm to realize the pre-welding teaching of curved welds. During the teaching process, the robotic arm controls the laser beam to move along the welding trajectory.

[0026] Welding trajectory compensation and correction: Based on the robot arm's taught motion trajectory of the laser beam, calculate the optimal geometric position of the laser welding head and the arc welding gun at each taught point;

[0027] Motion control programming: By controlling the rotation angle of the arc welding torch to change the geometric position state of the arc welding torch, motion control programming after welding trajectory compensation and correction is completed;

[0028] Laser-MIG arc synchronous motion welding: According to the determined composite welding parameters, confirm the geometric position of the laser arc, welding speed, laser power, welding current and other welding parameters, and carry out laser-MIG arc composite welding of curved welds according to the preset motion control programming program until the welding is completed;

[0029] Welding quality inspection: Non-destructive testing methods are used to inspect the welding quality. When the quality inspection fails, the defects should be repaired. The repaired welded parts should be re-inspected until they pass the inspection.

[0030] Furthermore, the method for calculating the optimal geometric position of the laser welding head and the arc welding gun at each teaching point includes the following steps:

[0031] Calculate the magnitude and direction of the forces exerted by the laser welding head and the arc welding gun;

[0032] Calculate the centrifugal force of the molten pool;

[0033] Adjust the angle of the arc welding gun to balance the forces applied by the laser welding head and the arc welding gun, the surface tension of the liquid metal in the molten pool, and the centrifugal force of the liquid metal in the molten pool.

[0034] (3) Beneficial effects

[0035] In this embodiment of the invention, the arc welding torch rotates around the axis of the laser beam, ensuring that the combined force of the laser welding head and the arc welding torch, the surface tension of the liquid metal in the molten pool, and the centrifugal force of the liquid metal in the molten pool remain balanced. This results in a more stable relative equilibrium state for the liquid metal in the molten pool, further mitigating the tendency for the liquid metal in the molten pool to excessively shift to one side, thereby avoiding problems such as poor fusion defects and / or undercut defects. The laser-MIG arc hybrid welding device of this embodiment is suitable for welding curved seams, which is beneficial for improving the welding quality of curved seams.

[0036] The laser-MIG arc hybrid welding method of this invention can automatically adjust the optimal geometric position of the laser welding head and the arc welding gun, ensuring that the centrifugal force of the liquid metal in the molten pool remains in a more stable relative balance, further alleviating the tendency of the liquid metal in the molten pool to shift excessively to one side, thereby avoiding the problems of poor fusion defects and / or undercut defects.

[0037] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0038] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the embodiments of the present invention will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0039] Figure 1 This is a schematic diagram of conventional curved weld seam welding in existing technology.

[0040] Figure 2 This is a top view of conventional curved weld seam welding in existing technology.

[0041] Figure 3 This is a schematic diagram of the position of laser-MIG arc hybrid welding according to an embodiment of the present invention.

[0042] Figure 4 This is a top view schematic diagram of a laser-MIG arc hybrid welding according to an embodiment of the present invention.

[0043] Figure 5 This is a schematic diagram of the structure of a laser-MIG arc hybrid welding device according to an embodiment of the present invention.

[0044] Figure 6 This is a schematic diagram of the structure of a connecting sleeve according to an embodiment of the present invention.

[0045] Figure 7 This is a flowchart of a laser-MIG arc hybrid welding method according to an embodiment of the present invention.

[0046] Figure 8 This is a schematic diagram of the forces acting on liquid metal in a molten pool according to an embodiment of the present invention.

[0047] In the diagram: 1-Laser beam; 2-Arc welding torch; 3-Welding trajectory; 4-Solidified metal; 5-Poor fusion defect; 6-Undercut defect; 7-Welding pinhole; 8-Arc action zone; 9-Molten pool; 10-Central plane of the arc; 11-Tangent line; 12-Laser welding head; 121-Focusing lens; 122-Anti-spatter lens; 13-Connecting seat; 131-Vertical plate; 132-Horizontal plate; 133-Sleeve; 1331-Through hole; 1332-Annular boss; 1333-External thread; 14-Drive device; 141-First gear; 15-First tapered roller bearing; 16-Rotating sleeve; 161-Second gear; 17-Second tapered roller bearing; 18-Threaded retaining ring; 19-Clamping arm; 20-Horizontal air curtain; 21-Base material. Detailed Implementation

[0048] The embodiments of the present invention will be further described in detail below with reference to the accompanying drawings and examples. The following detailed description of the embodiments and the accompanying drawings are used to illustrate the principles of the present invention by way of example, but should not be used to limit the scope of the present invention. That is, the present invention is not limited to the described embodiments, and any modifications, substitutions and improvements to the parts, components and connection methods are covered without departing from the spirit of the present invention.

[0049] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0050] The following will refer to the appendix. Figure 1 -Appendix Figure 8 This application will be described in detail with reference to the embodiments.

[0051] According to a first aspect of the present invention, a laser-MIG arc hybrid welding apparatus for curved welds includes:

[0052] Laser welding head 12, used to output laser beam 1 for welding;

[0053] Arc welding torch 2, used to output the welding arc;

[0054] The laser beam 1 output by the laser welding head 12 and the electric arc output by the arc welding gun 2 act on the same molten pool, and the arc welding gun 2 can rotate around the straight line direction of the laser beam 1 as an axis.

[0055] See the appendix below. Figure 3-5 and appendix Figure 8To illustrate embodiments of the present invention, as described in the background art, when welding curved welds, the molten pool 9 is subjected to centrifugal force. When the radius of curvature of the curved weld is less than a certain threshold, the centrifugal force of the liquid metal at the top of the local molten pool 9 may be greater than the surface tension of that area. The liquid metal in that area will tend to flow towards the solidified metal 4 on the outer side, causing undercut defects 6 to easily form on the weld face near the inner side of the curve, while poor fusion defects 5 are easily formed on the weld face away from the inner side of the curve. Based on this, the laser-MIG arc hybrid welding device for curved welds in this embodiment of the present invention includes: a laser welding head 12 and an arc welding torch 2. The laser beam 1 output by the laser welding head 12 and the arc output by the arc welding torch 2 act on the same molten pool. The laser-MIG arc hybrid welding method of the laser welding head 12 and the arc welding torch 2 can conveniently weld curved welds. The laser welding head 12 and the arc welding torch 2 can be used as needed, as shown in the attached figure. Figure 1 Or attached Figure 3 The arrangement of the laser beam 1 and the arc welding gun 2, which are two heat sources, one in front of the other, is not limited here.

[0056] To balance the centrifugal force of the molten metal generated during welding and prevent it from flowing out of the molten pool 9 and generating poor fusion defects 5 and / or undercut defects 6, the arc welding torch 2 of this embodiment can rotate around the straight line of the laser beam 1. This allows the arc welding torch 2 to rotate and adjust the direction of the magnetic blow-off force of the arc output by the arc welding torch 2. See Appendix Figure 8 As shown, this ensures that the resultant force F2 of the laser welding head 12 and the arc welding gun 2, the surface tension F3 of the liquid metal in the molten pool 9, and the centrifugal force F1 of the liquid metal in the molten pool 9 remain in balance. Specifically, in the attached... Figure 8 In the process, the resultant force F2 of the laser welding head 12 and the arc welding gun 2, according to the force decomposition, has a component force F in the opposite direction to the centrifugal force F1. 2x When F is maintained 2x When F3 = F1, the liquid metal in the molten pool 9 will remain in equilibrium and will not generate poor fusion defects 5 and / or undercut defects 6 under the action of centrifugal force F1.

[0057] In summary, in this embodiment of the invention, by rotating the arc welding torch 2 around the linear direction of the laser beam 1, the combined force F2 of the laser welding head 12 and the arc welding torch 2, the surface tension F3 of the liquid metal in the molten pool 9, and the centrifugal force F1 of the liquid metal in the molten pool 9 are kept in balance. This makes the liquid metal in the molten pool 9 maintain a more stable relative equilibrium state, further alleviating the tendency of the liquid metal in the molten pool to shift excessively to one side, thereby avoiding the problems of poor fusion defect 5 and / or undercut defect 6. The laser-MIG arc hybrid welding device of this embodiment of the invention is suitable for the welding process of curved welds, which is beneficial to improving the welding quality of curved welds.

[0058] Further, see appendix. Figure 5 As shown, according to an embodiment of the present invention, the laser-MIG arc hybrid welding device further includes: a connecting seat 13, a clamping assembly, and a driving assembly (the clamping assembly and driving assembly are not shown in the figure). Specifically, the laser welding head 12 is disposed on the connecting seat 13; the clamping assembly is rotatably connected to the connecting seat 13, and the clamping assembly is used to clamp the arc welding torch 2 and keep the arc welding torch 2 in a preset tilted state; the driving assembly is used to drive the clamping assembly and the arc welding torch 2 to rotate or position around the linear direction of the laser beam 1.

[0059] The following is in conjunction with the appendix Figure 5 To illustrate an embodiment of the present invention, in this embodiment, a laser welding head 12 is mounted on a connecting base 13. A laser beam 1 passes through the laser welding head 12 via a focusing lens 121 and irradiates the area to be welded. Simultaneously, a clamping assembly is rotatably connected to the connecting base 13. The clamping assembly clamps the arc welding torch 2 and maintains it in a preset tilted state, thus spatially offsetting the laser welding head 12 and the arc welding torch 2 to prevent interference. Furthermore, the laser beam 1 output from the laser welding head 12 and the arc magnetic force output from the arc welding torch 2 can act on the same molten pool 9 from different directions (e.g., one in front and one behind) for laser-MIG arc hybrid welding. Finally, a driving assembly in this embodiment drives the clamping assembly and the arc welding torch 2 to rotate around the laser beam 1 in a linear direction (i.e., along the adjacent direction). Figure 5 The laser welding head 12 rotates or positions itself in the vertical direction. Therefore, in the actual welding process, the angle of the output arc magnetic force of the arc welding gun 2 can be changed according to the magnitude and direction of the centrifugal force F1 of the liquid metal in the molten pool 9. This ensures that the combined force F2 of the laser welding head 12 and the arc welding gun 2, the surface tension F3 of the liquid metal in the molten pool 9, and the centrifugal force F1 of the liquid metal in the molten pool 9 remain in balance. This makes the liquid metal in the molten pool 9 maintain a more stable relative balance state, further alleviating the tendency of the liquid metal in the molten pool to shift excessively to one side, thereby avoiding the problems of poor fusion defect 5 and / or undercut defect 6.

[0060] Specifically, in one embodiment of the present invention, see appendix. Figure 5 As shown, the central axis of the arc welding torch 2 and the wire fed to it is perpendicular to the normal direction of the welding surface (see attached diagram). Figure 5 The tilt angle of the vertical dotted line (in the middle) is 30°-60°. The specific tilt angle can be selected according to the actual welding needs and is not limited here. Similarly, the wire extension length used in the arc welding gun 2 can be no more than 15mm, and the preset value range of the arc magnetic force position of the laser beam 1 and the arc welding gun 2 in the molten pool 9 can be 2mm-10mm; the diameter of the welding wire can be selected within the range of 0.8mm-1.6mm.

[0061] Further, see appendix. Figure 5 and 6 As shown, according to another embodiment of the present invention, the connecting seat 13 includes a horizontal plate 132 and a sleeve 133. The side of the laser welding head 12 that outputs the laser beam 1 is disposed on the horizontal plate 132. The sleeve 133 has a through hole 1331 in the middle for transmitting the laser beam 1. The central axis of the sleeve 133 coincides with the line where the laser beam 1 is located. In this embodiment of the present invention, on the one hand, the connecting seat 13 is provided to fix the laser welding head 12, so that the laser welding head 12 can be firmly fixed on the horizontal plate 132 of the connecting seat 13, and the laser beam 1 output by the laser welding head 12 can stably and accurately irradiate the molten pool 9, forming a laser-MIG arc composite welding together with the arc welding gun 2. On the other hand, the sleeve 133 can rotate relative to the clamping assembly together with the clamping assembly and can support the clamping assembly, so that the laser-MIG arc composite welding device of this embodiment of the present invention forms a complete structure (the specific structure of the clamping assembly and the specific connection method with the sleeve 133 will be disclosed in detail below).

[0062] Further, see appendix. Figure 5 and 6As shown, according to another embodiment of the present invention, the clamping assembly includes a rotating sleeve 16 and a clamping arm 19. The rotating sleeve 16 is sleeved on the outer peripheral wall of the sleeve 133, and a bearing is provided between the rotating sleeve 16 and the sleeve 133. One end of the clamping arm 19 is fixed to the outer peripheral wall of the rotating sleeve 16, and the other end of the clamping arm 19 is connected to the arc welding gun 2. In this embodiment of the invention, the rotating sleeve 16 is sleeved on the outer peripheral wall of the sleeve 133 and is connected in the middle by a bearing. Thus, the rotating sleeve 16 and the sleeve 133 can rotate relative to each other. The sleeve 133 can fix the laser welding head 12. The rotating sleeve 16 is connected to the arc welding gun 2 through the clamping arm 19. When the rotating sleeve 16 rotates relative to the outer peripheral wall of the sleeve 133, it drives the arc welding gun 2 to rotate relative to the axis of the laser beam 1. Therefore, when performing curved weld welding, the direction of the arc magnetic force applied by the arc welding gun 2 can be adjusted to ensure that the surface tension of the liquid metal in the molten pool 9 can be kept in balance and will not overflow to generate fusion defects 5 and / or undercut defects 6, etc.

[0063] Specifically, in one embodiment of the present invention, see appendix. Figure 5 As shown, a first tapered roller bearing 15 and a second tapered roller bearing 17 can be provided between the rotating sleeve 16 and the sleeve 133. The inner rings of the first tapered roller bearing 15 and the second tapered roller bearing 17 are fitted on the outer peripheral wall of the sleeve 133, and the outer rings of the first tapered roller bearing 15 and the second tapered roller bearing 17 are fitted on the inner wall of the rotating sleeve 16. The first tapered roller bearing 15 and the second tapered roller bearing 17 are used to realize the relative rotation between the rotating sleeve 16 and the sleeve 133.

[0064] Furthermore, according to another embodiment of the present invention, see appendix. Figure 5 As shown, the driving assembly includes a driving device 14, which drives the rotating sleeve 16 to rotate or position itself around the linear direction of the laser beam 1. As previously described, in this embodiment, the rotating sleeve 16 and the sleeve 133 can rotate relative to each other. The rotating sleeve 16 then drives the arc welding torch 2 to rotate via the clamping arm 19, thereby achieving the purpose of rotating the arc welding torch 2 around the linear direction of the laser beam 1. Based on this, this embodiment applies a force to the rotating sleeve 16 via the driving device 14, causing it to rotate or position itself around the linear direction of the laser beam 1, thus automatically achieving relative rotation between the rotating sleeve 16 and the sleeve 133.

[0065] Specifically, as shown in the attached document Figure 5As shown, the connecting seat 13 also includes a vertical plate 131, which is connected to the horizontal plate 132. The driving device 14 is fixedly connected to the vertical plate 131, thereby fixing the driving device 14. In this way, the driving device 14 and the connecting seat 13 remain relatively stationary during the actual driving process.

[0066] Specifically, in this embodiment of the invention, the driving device 14 can be a rotary motor. Thus, by power excitation, the rotation or stop of the driving device 14 can be easily controlled, achieving the purpose of rotating or positioning the rotating sleeve 16 around the linear direction of the laser beam 1 as a rotation axis. Furthermore, the rotary motor can be a stepper motor, which has the advantage of controllable step distance.

[0067] Furthermore, according to yet another embodiment of the present invention, see appendix. Figure 5 and attached Figure 6 As shown, one end of the outer peripheral wall of the sleeve 133 is provided with an annular boss 1332, and the other end of the outer peripheral wall of the sleeve 133 is provided with an external thread 1333. The rotating sleeve 16 is sleeved between the annular boss 1332 and the external thread 1333, and the external thread 1333 is threadedly connected to a threaded retaining ring 18. The annular boss 1332 can limit the rotating sleeve 16 from one side; the cooperation between the external thread 1333 and the threaded retaining ring 18 limits the rotating sleeve 16 from the other end. In this way, the rotating sleeve 16 is fixed in position on the sleeve 133, making it difficult for relative sliding to occur, and it is easy to control the position of the rotating sleeve 16, thereby ensuring that the position of the arc welding torch 2 is not easily moved relative to the outside. For details, please refer to the appendix. Figure 5 and attached Figure 6 As shown, the annular boss 1332 is located on the side close to the horizontal plate 132; correspondingly, the external thread 1333 is located on the side away from the horizontal plate 132.

[0068] Furthermore, according to yet another embodiment of the present invention, see appendix. Figure 5 As shown, the drive assembly also includes a first gear 141, and a second gear 161 is provided on the outer peripheral wall of the rotating sleeve 16. The first gear 141 and the second gear 161 mesh with each other for transmission. Through the meshing transmission of the first gear 141 and the second gear 161, the driving force of the drive device 14 can be accurately transmitted to the rotating sleeve 16. In addition, the drive device 14 can also drive the rotating sleeve 16 to rotate in other ways, such as by using a belt, direct drive by a rotating shaft, etc., which will not be described in detail here.

[0069] Specifically, in the embodiments of the present invention, the transmission ratio of the first gear 141 and the second gear 161 is in the range of 1-10. For example, the transmission ratio of the first gear 141 and the second gear 161 is 1, the transmission ratio of the first gear 141 and the second gear 161 can also be 10, etc., which will not be elaborated here.

[0070] Furthermore, according to one embodiment of the present invention, see appendix. Figure 5 As shown, the driving device 14 is fixed on the connecting seat 13, and the driving shaft of the driving device 14 is parallel to the rotation axis of the rotating sleeve 16. Specifically, as mentioned above, the driving device 14 is fixed on the vertical plate 131 of the connecting seat 13, and the vertical plate 131 is perpendicularly connected to the horizontal plate 132. The driving shaft of the driving device 14 is parallel to the rotation axis of the rotating sleeve 16. This ensures that the rotation direction of the driving device 14 is the same as the rotation direction of the rotating sleeve 16, which facilitates setting the position of the driving device 14 according to the rotation direction of the rotating sleeve 16, so that the rotation of the rotating sleeve 16 drives the arc welding gun 2 to rotate around the axis of the straight line where the laser beam 1 is located.

[0071] Furthermore, to protect the laser welding head 12, an anti-spatter lens 122 is provided between the laser welding head 12 and the sleeve 133. Simultaneously, to minimize welding spatter contamination of the anti-spatter lens 122, a cross-blowing air curtain 20 is also provided at the lower end of the sleeve 13. During welding, the inflation pressure of the cross-blowing air curtain 20 should not be lower than 0.3 MPa. The cross-blowing air curtain 20 can suppress welding spatter and debris, preventing contamination of the anti-spatter lens 122.

[0072] Furthermore, the laser beam 1 may include a non-scanning laser beam and a scanning laser beam, and the type of the laser beam 1 may include a fiber laser and a YAG laser. The focal length of the laser beam 1 may be between 150mm and 500mm, and the focal spot diameter of the laser beam 1 may be within a certain range. Between. When using a scanning laser beam, the scanning frequency of laser beam 1 can be adjusted between 30-300Hz, and the scanning amplitude can be adjusted within a certain range. Of course, specific operating parameters can be set as needed, which will not be elaborated here.

[0073] A laser-MIG arc hybrid welding method for curved welds according to a second aspect of the present invention, applied to an embodiment of the laser-MIG arc hybrid welding apparatus for curved welds according to any one of the first aspects of the present invention, see appendix. Figure 7 As shown, the laser-MIG arc hybrid welding method includes the following steps:

[0074] S120. Robotic Arm Teaching: A robotic arm is used to drive the laser-MIG arc hybrid welding device to achieve pre-welding teaching of curved welds. During the teaching process, the robotic arm controls the laser beam 1 along the path shown in the attached figure. Figure 3 The welding trajectory 3 shown is in motion;

[0075] S130, Welding trajectory compensation and correction: Based on the robot arm's taught motion trajectory of the laser beam 1, calculate the optimal geometric position of the laser welding head 12 and the arc welding gun 2 at each taught point; that is, as shown in the attached figure. Figure 4 As shown, the optical arc axial plane 10 at each teaching point position maintains an angle α with the tangent line 11 of the welding trajectory 3 at the laser action point.

[0076] S140, Motion control programming: By controlling the rotation angle of the arc welding torch 2, the geometric position state of the arc welding torch 2 is changed, and the motion control programming after welding trajectory compensation and correction is completed.

[0077] S150, Laser-MIG Arc Synchronous Motion Welding: According to the determined composite welding parameters, confirm the geometric position of the laser arc, welding speed, laser power, welding current and other welding parameters, and carry out laser-MIG arc composite welding of curved welds according to the preset motion control programming program until the welding is completed.

[0078] The laser-MIG arc hybrid welding method of this invention utilizes a robotic arm to achieve the revolution function of the laser-MIG arc hybrid welding. Combined with its own rotation function, it can maintain a preset angle α between the laser-MIG arc hybrid welding plane and the tangent of the welding trajectory 3 of the curved weld. This preset angle changes with the curvature radius of the curved weld. By changing the stress state of the liquid metal at the top of the molten pool 9, it affects the flow of liquid metal in the molten pool 9. This is especially beneficial for eliminating fusion defects 5 or undercut defects 6 that are prone to occur at the weld toe on the front side of the weld when the curvature radius of the curved weld is small, thus improving the quality of laser-MIG arc hybrid welding.

[0079] Simultaneously, relying on the robotic arm for teaching, during the teaching process, the robotic arm controls the laser beam 1 along the attached... Figure 3 The welding trajectory 3 shown is moved. Then, based on the teaching motion trajectory of the robot arm of the laser beam 1, the optimal geometric position state of the laser welding head 12 and the arc welding gun 2 at each teaching point is calculated. By controlling the rotation angle of the arc welding gun 2, the geometric position state of the arc welding gun 2 is changed, and the motion control programming after welding trajectory compensation and correction is completed. Then, the direction of the applied force of the arc welding gun 2 at each welding point can be automatically calculated, thereby ensuring that the liquid metal of the molten pool 9 at each welding point can maintain a more stable relative dynamic equilibrium state.

[0080] Furthermore, according to another embodiment of the present invention, the method for calculating the optimal geometric position of the laser welding head 12 and the arc welding gun 2 at each teaching point includes the following steps:

[0081] Calculate the magnitude and direction of the forces exerted by the laser welding head 12 and the arc welding gun 2;

[0082] Calculate the centrifugal force of the molten pool;

[0083] Adjust the angle of the arc welding gun 2 to balance the forces applied by the laser welding head 12 and the arc welding gun 2, the surface tension of the liquid metal in the molten pool 9, and the centrifugal force of the liquid metal in the molten pool 9.

[0084] As mentioned above and in conjunction with the appendix Figure 8 To illustrate an embodiment of the present invention, in order to balance the centrifugal force of the liquid metal generated during the welding process and prevent the liquid metal from flowing out of the molten pool 9 and generating poor fusion defects 5 and / or undercut defects 6, the arc welding torch 2 of the present invention can rotate around the straight line direction of the laser beam 1 as its axis. This allows the arc welding torch 2 to rotate and adjust the direction of the magnetic blow force of the arc output by the arc welding torch 2. In this embodiment of the present invention, the magnitude and direction of the forces exerted by the laser welding head 12 and the arc welding torch 2 are first calculated, and the centrifugal force of the molten pool is calculated (as mentioned above, this can be calculated using a robot arm teaching method and a computer); finally, based on the calculation results, the angle of the arc welding torch 2 is adjusted so that the forces exerted by the laser welding head 12 and the arc welding torch 2, the surface tension of the liquid metal in the molten pool 9, and the centrifugal force of the liquid metal in the molten pool 9 are balanced. (See attached...) Figure 8 In the process, the resultant force F2 of the laser welding head 12 and the arc welding gun 2, according to the force decomposition, has a component force F in the opposite direction to the centrifugal force F1. 2x When F is maintained 2x When F3 = F1, the liquid metal in the molten pool 9 will remain in equilibrium and will not generate poor fusion defects 5 and / or undercut defects 6 under the action of centrifugal force F1.

[0085] In summary, the embodiments of the present invention can automatically adjust the optimal geometric position of the laser welding head 12 and the arc welding gun 2, ensuring that the centrifugal force F1 of the liquid metal in the molten pool 9 remains in a more stable relative balance, further alleviating the tendency of the liquid metal in the molten pool to shift excessively to one side, thereby avoiding the problems of poor fusion defects 5 and / or undercut defects 6.

[0086] Further, see appendix. Figure 7 As shown, this embodiment of the invention further includes step S110, parts cleaning and assembly, before teaching the robotic arm. The parts cleaning and assembly steps include: cleaning the parts to be curved welded to thoroughly remove oil and oxide film from the surface of the parts; assembling and fixing the parts after cleaning; in this embodiment of the invention, to improve the welding effect, the maximum local assembly gap before welding is required to be no more than 0.5mm or 30%·δ (δ is the thickness of the welding base material 21), whichever is smaller; the maximum local misalignment is required to be no more than 0.2mm or 10%·δ (δ is the thickness of the welding base material 21), whichever is smaller. Of course, the specific values ​​of assembly gap and misalignment can be determined according to the actual situation.

[0087] Specifically, the part cleaning method in step S110 may include chemical cleaning, laser cleaning, etc. The part assembly is carried out by matching the corresponding welding tooling fixtures to ensure assembly accuracy and part surface accuracy.

[0088] Further, see appendix. Figure 7 As shown, this embodiment of the invention, after performing S150 (laser-arc synchronous motion welding), further includes step S160 (welding quality inspection). The specific method for welding quality inspection includes using non-destructive testing methods, such as X-ray inspection and penetrant testing. In step S160, if the quality inspection fails, the defective area should be repaired, and the repaired welded area should be re-inspected until it passes the inspection.

[0089] Specifically, in one embodiment of the present invention, the adjustment of parameters such as laser power and welding current in step S150 can adopt measures such as slow increase before welding and slow decrease after welding to further suppress welding defects such as porosity in the starting and ending welding areas, and further improve the welding quality of the starting and ending welding areas.

[0090] The following is in conjunction with the appendix Figure 1-8 The laser-MIG arc hybrid welding apparatus and hybrid welding method of the present invention will be illustrated by a specific embodiment.

[0091] The laser-MIG arc hybrid welding device of this invention includes: a laser welding head 12, an arc welding gun 2, a connecting seat 13, a clamping assembly, and a driving assembly. The laser welding head 12 outputs a laser beam 1 for welding, and the arc welding gun 2 outputs an arc for welding. The laser beam 1 output by the laser welding head 12 and the arc output by the arc welding gun 2 act on the same molten pool, and the arc welding gun 2 can rotate about the linear direction of the laser beam 1. The laser welding head 12 is mounted on the connecting seat 13; the clamping assembly is rotatably connected to the connecting seat 13 and is used to clamp the arc welding gun 2 and maintain it in a preset tilted state; the driving assembly drives the clamping assembly and the arc welding gun 2 to rotate or position themselves about the laser beam 1 in a linear direction. The connecting seat 13 includes a horizontal plate 132 and a sleeve 133. The side of the laser beam 1 output by the laser welding head 12 is disposed on the horizontal plate 132. The sleeve 133 has a through hole 1331 in the middle for the transmission of the laser beam 1. The central axis of the sleeve 133 is aligned with the laser beam 1. The clamping assembly includes a rotating sleeve 16 and a clamping arm 19. The rotating sleeve 16 is sleeved on the outer peripheral wall of the sleeve 133. One end of the clamping arm 19 is fixed to the outer peripheral wall of the rotating sleeve 16, and the other end of the clamping arm 19 is connected to the arc welding gun 2. A first tapered roller bearing 15 and a second tapered roller bearing 17 can be disposed between the rotating sleeve 16 and the sleeve 133. The inner rings of the first tapered roller bearing 15 and the second tapered roller bearing 17 are fitted onto the outer peripheral wall of the sleeve 133, and the outer rings of the first tapered roller bearing 15 and the second tapered roller bearing 17 are fitted onto the inner wall of the rotating sleeve 16. The first tapered roller bearing 15 and the second tapered roller bearing 17 are used to realize the relative rotation between the rotating sleeve 16 and the sleeve 133. The driving assembly includes a driving device 14, which is used to drive the rotating sleeve 16 to rotate or position around the linear direction of the laser beam 1 as the rotation axis. The connecting seat 13 also includes a vertical plate 131, which is connected to a horizontal plate 132. The driving device 14 is fixedly connected to the vertical plate 131, thereby fixing the driving device 14. One end of the outer peripheral wall of the sleeve 133 is provided with an annular boss 1332, and the other end of the outer peripheral wall of the sleeve 133 is provided with an external thread 1333. The rotating sleeve 16 is sleeved between the annular boss 1332 and the external thread 1333, and the external thread 1333 is threadedly connected to a threaded retaining ring 18. The drive assembly also includes a first gear 141, and a second gear 161 is provided on the outer peripheral wall of the rotating sleeve 16. The first gear 141 and the second gear 161 mesh with each other for transmission. The drive device 14 is fixed on the connecting seat 13, and the drive shaft of the drive device 14 is parallel to the rotation axis of the rotating sleeve 16. An anti-spatter lens 122 is provided between the laser welding processing head 12 and the sleeve 133, and a cross-blowing air curtain 20 is also provided at the lower end of the sleeve 13.

[0092] The following steps are used to weld a curved weld of 6061 aluminum alloy (3mm wall thickness) with a radius of curvature of 30mm using the aforementioned laser-MIG arc hybrid welding device:

[0093] S110: Parts cleaning and assembly. Clean the parts to be curved welded thoroughly to remove oil and oxide film from the surface; after cleaning, assemble and fix the parts, requiring that the maximum local gap before welding does not exceed 0.5mm and the maximum local misalignment does not exceed 0.2mm.

[0094] S120: Robotic arm teaching. A robotic arm drives a laser-MIG arc hybrid welding device to achieve pre-welding teaching of curved welds. During the teaching process, the robotic arm controls the laser beam 1 to move along the welding trajectory 3, that is, the robotic arm realizes the revolution function of hybrid welding.

[0095] S130: Welding trajectory compensation and correction. Based on the welding teaching trajectory of the laser beam, the optimal laser arc geometric position state of each teaching point is obtained through calculation, that is, the angle α = 10° between the central plane 10 of the optical arc at each teaching point and the tangent line 11 of the welding trajectory 3 at the laser action point is maintained. At this time, the MIG welding torch 20 and the laser beam 1 always maintain a paraxial state, and the inclination angle between the central axis of the MIG welding torch 20 and the welding wire and the normal of the welding surface is 45°. The wire extension is 10mm, the wire spacing is preset to 5mm, and the wire diameter is 1.2mm. The force on the liquid metal at the top of the molten pool 9 tends to be balanced, which solves the phenomenon that the molten pool tends to flow outward when the radius of curvature of the curved weld is small, and fundamentally suppresses the fusion defects or undercut defects at the weld toe position on the weld face.

[0096] S140: Motion control programming. By controlling the transmission ratio of the first gear 141 and the second gear 161 in the composite welding device to 3, the motion control programming after welding trajectory compensation and correction is completed. That is, the composite welding device realizes the real-time rotation and position adjustment of the MIG arc around the laser beam, which means that the self-rotation function of the composite welding device is realized.

[0097] S150: Laser-MIG arc synchronous motion welding. Following the taught welding trajectory, the welding parameters such as the arc geometry, welding speed, laser power, and welding current are reconfirmed. Specifically, the laser power is maintained at 2800W, the welding speed at 1.5m / min, and the MIG welding current at 60A. Finally, the laser-MIG arc hybrid welding of the curved weld is completed.

[0098] S160: Welding quality inspection. Non-destructive testing methods are used to inspect the welding quality. When the quality inspection fails, the defects exceeding the standard should be repaired. The repaired welded parts should be re-inspected until they pass the inspection. Inspection methods include X-ray inspection, penetrant testing, etc.

[0099] The above steps have been verified to effectively overcome the poor fusion or undercut defects at the weld toe on the front side of the weld that are prone to occur when the radius of curvature of the curved weld is small.

[0100] It should be noted that the various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. For the embodiments of the method, relevant parts can be referred to the description of the device embodiments. The present invention is not limited to the specific steps and structures described above and shown in the figures. Furthermore, for the sake of brevity, detailed descriptions of known methods and techniques are omitted here.

[0101] The above description is merely an embodiment of this application and is not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art without departing from the scope of the invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of this application should be included within the scope of the claims of this application.

Claims

1. A laser-MIG arc hybrid welding method for curved welds, employing a laser-MIG arc hybrid welding device, characterized in that, Laser-MIG arc hybrid welding equipment includes: A laser welding head (12) is used to output a laser beam (1) for welding. Arc welding torch (2) is a MIG welding torch used to output MIG arc for welding; The laser beam (1) output by the laser welding head (12) and the MIG arc output by the arc welding gun (2) act on the same molten pool (9), and the arc welding gun (2) can rotate around the straight line direction where the laser beam (1) is located. The laser-MIG arc hybrid welding method includes the following steps: Robotic arm teaching: The laser-MIG arc composite welding device is driven by a robotic arm to realize the pre-welding teaching of the curved weld. During the teaching process, the robotic arm controls the laser beam (1) to move along the welding trajectory (3). Welding trajectory compensation and correction: Based on the robot arm teaching motion trajectory of the laser beam (1), calculate the optimal geometric position state of the laser welding head (12) and the arc welding gun (2) at each teaching point, calculate the magnitude and direction of the force of the laser welding head (12) and the arc welding gun (2), calculate the centrifugal force of the liquid metal in the molten pool (9), and adjust the angle of the arc welding gun (2) so that the force applied by the laser welding head (12) and the arc welding gun (2), the surface tension of the liquid metal in the molten pool (9) and the centrifugal force of the liquid metal in the molten pool (9) are kept in balance; Motion control programming: By controlling the rotation angle of the arc welding gun (2) to change the geometric position state of the arc welding gun (2), the motion control programming after welding trajectory compensation and correction is completed; Laser-MIG arc synchronous motion welding: According to the determined composite welding parameters, the welding parameters of the laser arc are confirmed. The welding parameters include geometric position, welding speed, laser power, and welding current. The laser-MIG arc composite welding of the curved weld is carried out according to the preset motion control programming program until the welding is completed. Welding quality inspection: Non-destructive testing methods are used to inspect the welding quality. When the quality inspection fails, the defects should be repaired. The repaired welded parts should be re-inspected until they pass the inspection.

2. The laser-MIG arc hybrid welding method according to claim 1, characterized in that, The laser-MIG arc hybrid welding device also includes: Connecting seat (13), the laser welding head (12) is disposed on the connecting seat (13); A clamping assembly is rotatably connected to the connecting seat (13). The clamping assembly is used to clamp the arc welding gun (2) and keep the arc welding gun (2) in a preset tilt state. A driving component is used to drive the clamping component and the arc welding gun (2) to rotate or position themselves around the linear direction of the laser beam (1).

3. The laser-MIG arc hybrid welding method according to claim 2, characterized in that, The connecting seat (13) includes a horizontal plate (132) and a sleeve (133). The side of the laser welding head (12) that outputs the laser beam (1) is disposed on the horizontal plate (132). The sleeve (133) has a through hole (1331) in the middle for the transmission of the laser beam (1). The central axis of the sleeve (133) coincides with the line where the laser beam (1) is located.

4. The laser-MIG arc hybrid welding method according to claim 3, characterized in that, The clamping assembly includes a rotating sleeve (16) and a clamping arm (19). The rotating sleeve (16) is sleeved on the outer peripheral wall of the sleeve (133), and a bearing is provided between the rotating sleeve (16) and the sleeve (133). One end of the clamping arm (19) is fixed to the outer peripheral wall of the rotating sleeve (16), and the other end of the clamping arm (19) is connected to the arc welding gun (2).

5. The laser-MIG arc hybrid welding method according to claim 4, characterized in that, The driving assembly includes a driving device (14), which is used to drive the rotating sleeve (16) to rotate or position around the linear direction of the laser beam (1) as the rotation axis.

6. The laser-MIG arc hybrid welding method according to claim 4, characterized in that, One end of the outer peripheral wall of the sleeve (133) is provided with an annular boss (1332), and the other end of the outer peripheral wall of the sleeve (133) is provided with an external thread (1333). The rotating sleeve (16) is sleeved between the annular boss (1332) and the external thread (1333), and the external thread (1333) is threadedly connected with a threaded retaining ring (18).

7. The laser-MIG arc hybrid welding method according to claim 5, characterized in that, The drive assembly also includes a first gear (141), and a second gear (161) is provided on the outer peripheral wall of the rotating sleeve (16). The first gear (141) and the second gear (161) mesh with each other for transmission.

8. The laser-MIG arc hybrid welding method according to claim 5, characterized in that, The drive device (14) is fixed on the connecting seat (13), and the drive shaft of the drive device (14) is parallel to the rotation axis of the rotating sleeve (16).

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